Having said this much, to make the Unity of the Judgment unmistakable, we may now safely distinguish between the Subject and Predicate in the Judgment. And we shall find the safest clue to be that the explicit Subject, when there is one, marks the place at which, or the conditions under which, Reality accepts the Predicate. The natural Subject is concrete, and the Predicate abstract; the Subject real, and the Predicate ideal, but pronounced to be real. The reason of this is that every Judgment is the connection of parts in a whole, and to be a whole is the characteristic of reality. In other words, the natural course of thought is to define further what is already in great part defined, and our real world is that which we have so far defined. The isolated judgments of the text-books make it very hard to grasp this, because you seem to begin anywhere for no connected reason at all. But if we reflect on actual thought, { 109} we find that, as Mr. Stout very cleverly says, we are always developing a “subject” which is in our minds (in the ordinary sense of a “subject of conversation”), and this subject is some region or province of the world of reality.
Now the explicit Subject in Judgment or the grammatical Subject in Proposition does not always set out the full nature of this, but merely some mark or point in it which we wish to insist upon. So that we may find in Judgment almost anything serving as explicit Subject. Thus, as Aristotle said quite plainly and sensibly, it is natural to say “The horse is white,” but we _may_ have occasion to say “This white is a horse”; it depends on the way in which the Subject comes into our minds. [1] Usually the Subject will be what Dr. Venn calls the heavier term, _i.e._ the term with more connotation. When there is no difference of concreteness between parts and whole, the Judgment becomes reversible as in the equation 7 + 5 = 12. There is no distinction here between Subject and Predicate. The real underlying unity or Subject is the numerical system.
[1] See Prof. Bain, p. 56, upon the Universe, and Universe of Discourse, _i.e._ the general subject which you have in your mind.